// $(function () {
//     window
// })
















var ding_ele  = document.querySelector(".ding");
window.onscroll = function () {
    var scrollTop = document.body.scrollTop || document.documentElement.scrollTop;
    
    if(scrollTop >700){
        ding_ele.style.position = "fixed";
        ding_ele.style.left = "0px";
        ding_ele.style.top = "0px";
        // ding_ele.style.background = "#fff";
    }else{
        ding_ele.style.position = "static";
    }
}